Table 3-16a. Respirable quartz: Geometric mean exposures and percent exceeding designated occupational exposure limits in coal mining, MSHA inspector and mine operator samples, 1982–2003
- incalculableSIC - Standard Industrial ClassificationPEL - permissible exposure limitREL - recommended exposure limitGM - geometric meanmg/m3 - milligrams per cubic meterMRE - Mining Research Establishment
Note: The MSHA PEL is 2 mg/m3 MRE for respirable dust containing less than or equal to 5 percent quartz. The PEL is adjusted using the formula [(10 mg/m3 MRE) / (% quartz)] for respirable dust containing greater than 5 percent quartz. See appendices for sourc
Source: MSHA coal mine inspector and mine operator quartz data.
